Thus has the evolution of manufactured computing systems to the
present been backward to the evolution of natural computing systems
such as the brain. The brain appeared only recently in the scope of
the history of life on earth--and is no great shakes as a
general-purpose algorithmic computing device--but from the beginning
it has been richly interconnected to a body possessing sensory-motor
apparatus that beggars anything we are currently able to manufacture
at any price. The body has an extensive array of active and passive
defense mechanisms, and the brain has extensive hardware support for
threat assessment, triage, extrapolation, and rapid response.

The living computation perspective predicts that we are nearing
childhood's end for computers, that current designs--still steeped in
their innocent, safe, and externally-protected origins--will give way
to designs possessing significant kinesthetic senses, defense and
security at many levels, and with rich and persistently paranoid
internal models representing the body and the stance of the body
within the larger computational and physical environment.1

Manufactured computers began as `pure mind designs' but were not
thereby excused from the demands of existing in the physical world.
With the rise of networked computing, and the rise of computers
intended to survive in consumer environments and without the benefit
of an expert human system administrator, the `IOU: A body' notes
issued fifty years ago and more are now rapidly coming due.